RIS Assembly Positioning for Higher-Rank Wireless Channels
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Solution Overview
Problem
Existing wireless communication systems using reconfigurable intelligent surfaces (RIS) face limitations in serving multiple user terminals due to low rank propagation channels, especially at high frequencies, which restrict spatial multiplexing gains, and direct visibility scenarios act as bottlenecks.
Innovation Solution
Positioning a set of reconfigurable intelligent surfaces, including a main RIS and intermediate RISs, to optimize path gains by determining their positions and orientations based on distance and angle parameters, using constrained gradient descent algorithms to maximize signal propagation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single RIS is deployed to create an indirect path between base station and user terminals, then coverage in obstructed areas is improved, but the rank of propagation channels remains low which limits spatial multiplexing gains
Solution Approach 1:
The patent divides a single RIS into multiple separate RISs (first RIS and second RIS) that work together to create indirect paths. This segmentation allows each RIS to be positioned independently to serve different spatial directions, thereby increasing the overall channel rank and spatial multiplexing capability while maintaining improved coverage in obstructed areas.
2Reliability
If RISs are positioned to maximize path gain between base station and user terminals, then signal quality is improved, but the complexity of positioning and configuration increases
Solution Approach 1:
The patent introduces a controller as an intermediary device that automatically determines the optimal positioning and configuration parameters for multiple RISs. This controller calculates the necessary phase shifts and positioning based on channel state information, thereby maintaining high signal quality while reducing the operational complexity for manual configuration and deployment.
3Adaptability or versatility
If multiple RISs are deployed to increase channel rank for spatial multiplexing, then spatial multiplexing gains are improved, but the device complexity and deployment difficulty increase
Solution Approach 1:
The patent designs each RIS with universal functionality to reflect signals in multiple directions by adjusting phase shifts of reflection elements. This multi-functionality allows each RIS to adapt to different spatial configurations and serve multiple user terminals simultaneously, thereby achieving high spatial multiplexing gains without proportionally increasing deployment complexity.
Solution Approach 2:
The controller acts as an intermediary that automatically manages the configuration and coordination of multiple RISs. It determines optimal positioning and phase shift parameters based on channel conditions, which simplifies the deployment process and reduces the complexity of managing multiple RIS units while maintaining high spatial multiplexing performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the quality of service by increasing the rank of propagation channels and ensuring path gains exceed predetermined thresholds, thereby improving spatial multiplexing capabilities and coverage.
Implementation Method 1
a reconfigurable intelligent surface, hereinafter "RIS" (acronym for the English expression "Reconfigurable Intelligent Surface") for brevity, can be defined as a relay configured to receive an incident signal from a transmitter and reflect it in a specific direction
Implementation Method 2
By modifying the reflection properties of each reflection element of the RIS, typically by individually modifying the phase shift introduced by each of these reflection elements, it is possible to influence the way in which the incident radio signals are reflected by the RIS
Data Source
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AI summary
The invention relates to a method for positioning a set E of reconfigurable intelligent surfaces associated with an access point (21) of a telecommunications network. The set comprises at least one reconfigurable intelligent surface called "intermediate surface" and at least one other reconfigurable intelligent surface called "main surface". The method notably comprises a determination (S100) of positioning data of the intermediate and main surfaces such that signals emitted by the access point (21) are reflected by the intermediate surface (20_j = 1.. 3) towards the main surface (20_i) to exchange data with at least one user terminal (23) located in the geographical area served by the main surface, but also such that a path gain of a path taken by said signals between the access point (21) and this user terminal (23) is greater than a predetermined or maximized threshold.